Compaq ProLiant 1000 Architecting and Deploying High-Availability Solutions - Page 3

Architecting and Deploying High-Availability Solutions 3 Introduction When the systems that run your organization1 are down the costs can be devastating. Lost opportunities. Lost revenues. Failure-to-perform fees. Non-compliance penalties. Plus stranded fixed costs you have to keep on paying whether your people are productive or not. Potentially more damaging is a nearly incalculable loss: the loss of good will. Customers, partners, and suppliers affected by system shutdowns perceive your organization as poorly run and ill-suited to meeting their needs. Thus, the starting point for any discussion of availability has to be the cost of information system downtime to your organization. The higher the cost of downtime, the more robust the availability environment needs to be. And the more successful your environment is in delivering the level of availability required by the organization, the faster the return on your investment. The purpose of this white paper is to provide an overview of the factors that - taken together - define your availability needs and how Compaq Computer Corporation can meet them. Definitions Before proceeding with a discussion of high availability, it is helpful to define a few terms. Availability: The ratio of the total time a functional unit is capable of being used during a given interval to the length of that interval. It is the proportion of time a system is productive which implies performance. Mission Critical: A term applied to information systems upon which the success of an organization depends and the loss of which results in unacceptable functional or financial harm. Mean Time Between Failure(MTBF): a statistically derived length of time a user may reasonably expect a component, device, or system to work between two incapacitating failures. Reliability: A measure of how dependable a system is once you actually use it. Reliability can also be considered the sum of availability and data integrity. Determining Availability Requirements Determining an organization's availability requirements and architecting a system to meet them is a multistep process. 1. Determine the cost of downtime. (Page 4) 2. Understand recovery in terms of point and time. That is, when is recovery necessary in the system's operations and how long a time exists between the point of failure and recovery. (Page 5) 3. Focus on the events that can have a negative impact on the ability to keep an application -- and an organization -- up and running. Understanding these events is essential for developing the right highavailability environment for your organization. (Page 6) 4. Understand the vulnerability of various systems with respect to the above. (Page 7) 5. Once you understand the events that lead to downtime, determine which technology areas you will need to focus on to achieve the level of availability required. (Page 8) 6. When all these factors are understood, architect and deploy the availability environment. (Page 9) 1 As used in this white paper, organization means any entity that requires computing technology to achieve its goals and conduct its operations. Examples include businesses, departments of businesses, academic institutions, research facilities, or military units. ECG064/1198